Treatments and outcomes of patients with localized extranodal NK/T-cell lymphoma (ENKL) diagnosed between 2014 and 2021: A cooperative study in Japan.
Authors: Kana Miyazaki, Ayumi Fujimoto, Senzo Taguchi, Naoko Asano, Wataru Munakata, Mitsuhito Hirano, Masahiro Takeuchi, Jun Amaki, Jun Takizawa, Noriko Fukuhara, Rika Sakai, Takeshi Maeda, Toshiyuki Imagumbai, Yuri Miyazawa, Yoshihiro Kameoka, Makoto Yoshimitsu, Isao Tawara, Yasuo Ejima, Ritsuro Suzuki, Motoko Yamaguchi
Journal: Journal of Clinical Oncology (2023)

7565 Background: A previous cooperative study of patients (pts) with ENKL who were diagnosed between 2000 and 2013 in 31 institutes in Japan reported that the most common first-line treatment for localized ENKL was radiotherapy with dexamethasone, etoposide, ifosfamide, and carboplatin (RT-DeVIC) (66%). The 2-year (yr) overall survival (OS) and progression-free survival (PFS) of pts with localized ENKL were 78% and 68%, respectively (JCO 2017). RT-DeVIC has been included as a preferred regimen of combined modality therapy in the NCCN guidelines. The treatments and outcomes of pts with localized ENKL in recent clinical practice are unknown. Methods: We conducted a cooperative study (NKEA-Next; UMIN000046300) by hemato-oncologists and radiation oncologists of pts with ENKL who were diagnosed between 2014 and 2021 in 45 institutes in Japan. The results were compared with those from the 2000-2013 cohort (JCO 2017). The primary endpoint was OS of pts with ENKL who received next-generation treatment in 2014-2021 at participating institutes. We analyzed the data of localized ENKL. Results: Of 351 pts in the 2014-2021 cohort, 235 (67%) had localized ENKL. First-line therapy was RT-DeVIC in 185 (79%) pts, sequential chemoradiotherapy in 17, RT alone in 15 pts, and chemotherapy alone in 12 pts. Six pts received no treatment due to poor performance status (PS). Only two pts (1%) received anthracycline-containing regimens. With a median follow-up of 3.4 yrs, the 2-yr OS and PFS of localized ENKL were 83% and 75%, respectively. Pts treated with RT-DeVIC showed the following clinical features: median age, 58 yrs (range, 13-82); age &gt; 60 yrs, 45%; stage IIE, 34%; B symptoms present, 27%; elevated serum lactate dehydrogenase, 23%; ECOG PS 2, 4%; and soluble interleukin-2 receptor (sIL-2R) level &gt; upper limit of normal (ULN), 31% (57/183). The complete response rate was 88% among the 179 pts who were evaluated for response. The 2-yr OS and PFS of RT-DeVIC were 87% and 79%, respectively. There was no treatment-related death due to RT-DeVIC. G3/4 mucositis was recorded in 32% (G3, n = 59; G4, n = 0). G3/4 febrile neutropenia occurred in 18% (G3, n = 32; G4, n = 2). sIL-2R &gt; ULN was associated with worse OS ( P &lt; 0.01). In comparison with pts with localized disease in the 2000-2013 cohort, pts in the 2014-2021 cohort received RT-DeVIC more frequently ( P &lt; .001). There was no significant difference in OS ( P = 0.24) or PFS ( P = 0.10) between the two cohorts. Conclusions: RT-DeVIC was more frequently used for first-line treatment of localized ENKL, and its efficacy has been maintained, with 87% 2-yr OS in recent clinical practice in Japan, providing further evidence of RT-DeVIC as a preferred first-line regimen for localized ENKL. No obvious improvement in OS and a reduction in G3 mucositis were observed, suggesting that more efficacious and less toxic regimens need to be introduced.